The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Referring now to FIG. 1, a prior art throttle control system 10 for use with an internal combustion engine 14 is shown. Throttle control system 10 includes a throttle body 12 that throttles air to the engine 14 based on a throttle control signal 16. Throttle body 12 includes first and second throttle position sensors 18, 20 that generate respective throttle position signals. Each throttle position signal 18, 20 indicates the same degree of opening of throttle body 12. Using the two throttle positions signals provides redundancy that improves self-diagnostic capabilities. An analog-to-digital converter module 22 digitizes each throttle position signals. A diagnostic module 24 compares the signals to each other and to predetermined diagnostic thresholds. Results of the comparisons indicate whether throttle position signals are valid or corrupted. Examples of corrupted signals include shorted to ground, shorted to a signal excitation voltage, and irrational.
Referring now to FIG. 2, a second embodiment is shown of a throttle control system 10′ having a single throttle position sensor. Dual throttle position sensors, such as that illustrated in FIG. 1, are typically not used. Currently, most vehicles use a single throttle position sensor 18 and an analog-to-digital converter 22 that generates a single throttle position sensor signal TP1. However, it is expected that the use of dual throttle position sensing systems will expand. However, single throttle position sensing systems will continue to be used for many years.
The diagnostic module 24′ includes diagnostics for diagnosing errors in the single throttle position signal whereas the diagnostic module 24 of FIG. 1 includes diagnostics for sensing errors in two throttle position sensors. Developing and maintaining two sets of diagnostic codes is expensive since two sets of diagnostic codes and two sets of software codes must be maintained.